With the rapid development of the internet and popularization of large screen multifunctional mobile terminals such as mobile phones, many mobile data multimedia services and various high bandwidth multimedia services, such as video conferencing, telecasting, video-on-demand, video advertisement, on-line education, interactive gaming, and the like, emerge, not only meeting the rising service requirement of mobile users, but also bringing new service growth point for a mobile operator. These mobile data multimedia services require that the same data can be received by multiple users simultaneously, and are characteristic of large data sizes, long duration, time-delay sensibility, and the like compared with an ordinary data service. In order to utilize mobile network resources effectively, the 3rd Generation Partnership Project (3GPP) proposes a Multimedia Broadcast Multicast Service (MBMS) which is a technique of transferring data from one data source to multiple targets, realizing resource sharing of a network including a core network and an access network and enhancing the utilization rate of network resources especially air interface resources. The MBMS defined by 3GPP can implement not only plain-text-low-speed-message-type multicasting and broadcasting, but also high-speed-multimedia-service's broadcasting and multicasting, providing all kinds of abundant video, audio, and multimedia services, which doubtlessly conforms to the trend for future mobile data development and provides a better service prospect for development of the 3rd Generation (3G) digital communications.
In LTE-Advanced (LTE-A), multi-carrier aggregation is introduced, namely, there are multiple carriers of different (continuous or discrete) frequencies (frequency bands); a network side uses two or more carriers simultaneously to send data for one UE, which receives data on two or more carriers simultaneously. According to the current progress of standard-making, the following conclusions are adopted by standardization organizations and are written into corresponding protocols.
The multi-carrier aggregation technology specification is as follows:                each UE supports aggregation of at least 2 Component Carriers (CC);        a network side allocates for the UE and indicates which one is the Primary Cell (Pcell) of the UE, and which ones are the Secondary Cells (Scell) of the UE;        a UE in an idle state stays in its Pcell;        the Pcell always remains in an activated state;        the network side can close (or deactivate) and open (or activate) an Scell of the UE;        the UE does not receive a Physical Downlink Control Channel (PDCCH) in a closed Scell;        the UE does not receive a Physical Downlink Shared Channel (PDSCH) in the closed Scell;        the UE does not perform downlink carrier Channel Quality Indicator (CQI) measurement in the closed Scell;        the initial default state of an Scell is the deactivated state;        the UE receives a Broadcast Control Channel (BCCH) and a Paging message only in the Pcell.        
Based on the aforementioned conclusions, we analyzed and found the following issues, specifically as follows:
Assuming an MBMS is being sent from a Multimedia Broadcast multicast service Single Frequency Network (MBSFN) area, and assuming further that within the MBSFN area, there are multiple CCs in some cells, in which CC2 is being used to send the MBMS in an MBSFN manner, it can be assumed that there are 3 CCs, noted as CC1, CC2, and CC3, respectively, in the cell(s). It can be assumed further that in the cell(s), the Pcells of some UEs are configured to be CC2, the Pcells of some UEs are CC1 or CC3, that is, for some UEs, CC2 is their Scell.
The aforementioned scenario is a very common one in a system with carrier aggregation as the main technique, which scenario however, according to existing carrier aggregation criterion requirement, has a certain problem in that a network side can configure, open, and close the UE's Scell for the UE, and the current condition for opening and closing Scells is determined based on a requirement related to a unicast service without considering requirements relevant to an MBMS. Then, if the network side closes Scells of some UEs, which Scells are CC2, then those UEs, according to existing technical criterion requirement, can not receive a PDCCH, a PDSCH, a BCCH, a paging message, and the like in their closed Scells (CC2), which limitation eventually leads to incapability of the UEs to receive an MBMS on their CC2. The reason of this is that the UEs can not receive a PDCCH and a BCCH in a closed Scell, and the network side does not know the relevant information on receiving of an MBMS by the UEs, that is, whether the UEs are receiving the MBMS, nor the state of the UEs (a connected state or an idle state), thus when closing an Scell, the network side does not refer to the MBMS receiving circumstance of the UEs, which leads to the aforementioned problem.
Another circumstance will also result in incapability of receiving an MBMS by a UE, namely, the UE wants to receive an MBMS on a certain CC bearing the MBMS, which however is not included in the CCs allocated to the UE by the network side. Thus, according to provisions of existing technical criterion, the UE can not receive the MBMS from the CC, which mainly is caused because the network side does not know the receiving requirement of the UE.
From the above analysis, the present disclosure proposes the following perfecting technical solution to implement receiving of the MBMS by the UE in a multi-carrier system.